1. Field of the Invention
The present invention relates to an apparatus for shutting off a power supply for a vehicle, and more particularly, the present invention relates to an apparatus for shutting off a power supply for a vehicle, which can stably shut off a power supply to functional electrical devices and reduce power consumption through the use of minimum power even if a key switch is in a turned-on state. Specifically, the present invention relates to an apparatus for shutting off a power supply for a vehicle, in which a controller grasps an operator's intention to manipulate equipment, and if there is no intention for an operator to manipulate the equipment for a predetermined time, the controller turns off an engine start regardless of the operation of the key switch, and shuts off the power supply to the functional electrical devices connected to a battery to prevent the discharge of the battery which may occur due to an engine stop. Also, the present invention relates to an apparatus for shutting off a power supply for a vehicle, which can prevent deterioration of the reliability in comparison to a power supply system by an electrical circuit in the related art even though the power is controlled by the controller on a normal operation condition.
2. Description of the Prior Art
According to an apparatus for shutting off a power supply for a vehicle in the related art, as illustrate in FIG. 1, if a key switch 101 is turned on, a controller (electronic control unit (ECU)) 104 operates, and at this time, the controller (ECU) 104 supplies power to a functional electrical device (not illustrated) by driving a main relay 102.
If an operator gets out of equipment in a state where the key switch 101 is in a turned-on state and an engine is operated, and a predetermined time elapses after the controller (ECU) 104 senses that there is no further manipulation of a control lever 103, the controller (ECU) 104 sends an engine stop signal to an engine ECU. When the engine ECU receives this signal, it stops fuel injection and then stops the engine.
If the engine is stopped, an alternator stops generation of the electricity. In this case, since the functional electrical devices connected to the main relay 102 are driven only by the battery, the battery may be discharged while the engine stop state is maintained for a long time.
In order to solve such battery discharge phenomenon, as illustrated in FIG. 2, the controller (ECU) 104 has been changed to have a structure that drives the main relay 102 by the key switch signal.
However, in order to prevent the battery discharge after the engine stop, it is required to continuously supply the power to the controller (ECU) 104 so that the controller (ECU) 104 turns off the main relay 102 to shut off the power supply.
Here, since the controller (ECU) 104 has relatively complicated components and control algorithms, it is sensitive to external environmental conditions, it is often difficult to completely cut off malfunction caused by the environmental change. Accordingly, due to the incomplete operation of the controller (ECU) 104, it is expected that the power supply to the main relay 102 may be unstable.
Also, in order to implement a backup means for making it possible to perform the basic operation of the equipment even though trouble occurs in the controller (ECU) 104, a separate circuit is required, and this cause the increase of the manufacturing cost and the complexity of the system.
On the other hand, according to the apparatus for shutting off a power supply for a vehicle in the related art, as illustrated in FIG. 1, if the key switch 101 is turned on, the controller (ECU) 103 operates and controls the main relay 102 to supply the power to the functional electrical devices.
If it is required to shut off the power supply even through the key switch 101 is in a turned-on state, the controller (ECU) 103 shuts off the power supply to the main relay 102 by cutting off the output connected to a driving unit of the main relay 102.
In this case, the controller (ECU) 103 continuously consumes the power, and in the case of a power system using a battery, the battery voltage becomes lowered to shorten the lifetime of the battery.
Also, the main relay 102 directly controls the controller (ECU) 103, and thus if the reliability of the controller (ECU) 103 is not high, the power may be not appropriately supplied to the devices.
As described above, according to the apparatus for shutting off the power supply for a vehicle in the related art, if it is intended to optionally shut off the power supply by the controller (ECU) 103 in turned-on state of the key switch 101, it is required for the controller (ECU) 103 to continuously apply the power, and in this case, the continuous use of the electricity is unavoidable. Also, if the controller (ECU) 103 is unstable even in a normally used state, the main relay 102 may be turned off to cause all the functional electrical devices to be unusable.